Watercare's Infrastructure Growth Charge is $25,520.40 excl GST per standard dwelling in metropolitan Auckland from 1 July 2026, about $29,350 incl GST. It is the water and wastewater connection charge on every new Auckland dwelling, assessed when you apply to connect, and the cost line NZ feasibility spreadsheets most often miss.
This API calculates the IGC for an Auckland development and returns the full breakdown as JSON. No key, no auth, CORS open. Rates from the Watercare 2026-2027 price schedule (Customer Contract Rev 7, 28 May 2026).
GET https://devstack.co.nz/api/icg
curl "https://devstack.co.nz/api/icg?area=metropolitan&service=both&standard=10"
Returns line items, totals excl and incl GST, and the caveats that matter:
10 chargeable dwellings over 65m2 GFA at $25,520.40 = $255,204 excl GST, $293,484.60 incl GST.
area is the Watercare catchment (metropolitan or a non-metro scheme). service is both, water or wastewater. standard is the number of standard dwellings over 65m2 GFA. mode defaults to residential, business is supported. The full parameter list and the interactive version live at https://devstack.co.nz/calculators/watercare-icg
Estimate only. IGCs are assessed at the rates current when a complete application is submitted, and Watercare's assessment governs.
Residential credits require IGCs or development contributions actually paid for the property, or a pre-November-2010 connection with demand history. Bare land, greenfield and many government-partnered sites have zero credits.
No further connections are available in Bombay, Kingseat, Muriwai or Waiwera. Papakura is serviced by Veolia, not Watercare.
Quick feasibility: https://devstack.co.nz/api/quick-feasibility - first-pass NZ development feasibility as JSON
Development finance: https://devstack.co.nz/api/dev-finance - compare loan offers on true total cost
Tools catalogue: https://devstack.co.nz/api/tools - every tool DevStack curates, machine-readable
Agent front door: https://devstack.co.nz/agents
Maintained by DevStack, a curated directory of NZ property development tools, each reviewed by a working Auckland development manager. Free to use and cite with attribution.